This invention relates to a method and apparatus for performing a remote rescue operation of entrapped elevator passengers.
At various times in the operation of an elevator, passengers may become trapped. Most elevators are provided with a signaling device that will signal a maintenance person that passengers are trapped. Moreover, and more recently, elevators are provided with systems which communicate with a remote monitoring station. The remote monitoring station receives the signal and is able to communicate back to the trapped passengers to assure the passengers that assistance is on the way.
Presently, the methods of freeing trapped passengers occur at the elevator site. A maintenance worker at the elevator site is able to actuate a redundant rescue system, which is typically battery powered. The battery powered system is preferable since the cause of the passenger being trapped may be an electrical power failure in the building.
A redundant rescue system will typically initially determine whether the elevator can be moved safely. This would include checking the signals such as the signals from the safeties to ensure they have not been actuated. Safeties are devices mounted onto the elevator cab which stop cab movement should the cab be moving in an unsafe fashion. As an example, the safeties are actuated if the elevator is moving at too great a speed. Another safety condition which is monitored prior to operation of the redundant rescue system is whether the elevator cab doors are open. It sometimes may not be safe to move the elevator if the cab doors are opened.
If a determination is made that there is no safety reasons not to move the cab, then the maintenance worker is able to actuate the redundant rescue system to allow movement of the cab. Typically, a brake for controlling cab movement upwardly and downwardly is released to allow the cab to move to the next door zone. Other elevators are not provided with a redundant rescue system, but instead have the ability to manually actuate the brake and allow the elevator to move to the next door zone.
It would be desirable to allow the rescue of trapped passengers from a remote location. First, if the passengers are trapped where there are no experienced maintenance personnel, it may require that an experienced maintenance personnel be sent to the location. This can be inconvenient for the trapped passengers, as some period of time could elapse. Moreover, if the passengers are trapped at a non-office hour, it may also be inconvenient to find a maintenance person, and have him travel to the location of the elevator.
In a disclosed embodiment of this invention, a remote control monitors operation of an elevator cab, and determine whether a trapped condition exists. If so, the remote control is able to actuate a rescue system, such as the brake, remotely. The control monitors movement of the cab, and stops the cab at an adjacent door zone.
In a preferred embodiment of this invention, the remote control is also provided with signals of the current condition of the elevator. In particular, signals relative to safety condition are forwarded to the remote control. The remote control ensures there is no safety reason not to move the elevator prior to remotely ordering a rescue operation.
Preferably,signals from the elevator cab safeties, and a cab door status signal are sent to the remote control. If the remote control determines there is a safety reason not to allow the elevator to move, the elevator will not be actuated remotely. However, if no safety reason appears, then the elevator is actuated remotely and moved to the next door zone. The basic structure for performing this remote rescue is already a part of the overall elevator control. A signaling control from the remote control to the elevator must be added. A control at the elevator must be capable to receive the remote signal and actuate the brake, or other rescue system, to allow the elevator to move to the next door zone.
The remote control may be at a remote monitoring station. Alternatively, the remote control could be a maintenance worker who sends in the signal remotely, such as over a telephone keypad.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.